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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

University of Kentucky

2018

Active galaxies

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

The Nature Of Deeply Buried Ultraluminous Infrared Galaxies: A Unified Model For Highly Obscured Dusty Galaxy Emission, J. A. Marshall, Moshe Elitzur, L. Armus, T. Diaz-Santos, V. Charmandaris May 2018

The Nature Of Deeply Buried Ultraluminous Infrared Galaxies: A Unified Model For Highly Obscured Dusty Galaxy Emission, J. A. Marshall, Moshe Elitzur, L. Armus, T. Diaz-Santos, V. Charmandaris

Physics and Astronomy Faculty Publications

We present models of deeply buried ultraluminous infrared galaxy (ULIRG) spectral energy distributions (SEDs) and use them to construct a three-dimensional diagram for diagnosing the nature of observed ULIRGs. Our goal is to construct a suite of SEDs for a very simple model ULIRG structure, and to explore how well this simple model can (by itself) explain the full range of observed ULIRG properties. We use our diagnostic to analyze archival Spitzer Space Telescope Infrared Spectrograph data of ULIRGs and find that: (1) in general, our model does provide a comprehensive explanation of the distribution of mid-IR ULIRG properties; (2) …


Intermediate-Line Emission In Agns: The Effect Of Prescription Of The Gas Density, T. P. Adhikari, K. Hryniewicz, A. Różańska, B. Czerny, Gary J. Ferland Mar 2018

Intermediate-Line Emission In Agns: The Effect Of Prescription Of The Gas Density, T. P. Adhikari, K. Hryniewicz, A. Różańska, B. Czerny, Gary J. Ferland

Physics and Astronomy Faculty Publications

The requirement of an intermediate-line component in the recently observed spectra of several active galactic nuclei (AGNs) points to the possible existence of a physically separate region between the broad-line region (BLR) and narrow-line region (NLR). In this paper we explore the emission from the intermediate-line region (ILR) by using photoionization simulations of the gas clouds distributed radially from the center of the AGN. The gas clouds span distances typical for the BLR, ILR, and NLR, and the appearance of dust at the sublimation radius is fully taken into account in our model. The structure of a single cloud is …


Luminous And Obscured Quasars And Their Host Galaxies, Agnese Del Moro, David M. Alexander, Franz E. Bauer, Emanuele Daddi, Dale D. Kocevski, Flora Stanley, Daniel H. Mcintosh Jan 2018

Luminous And Obscured Quasars And Their Host Galaxies, Agnese Del Moro, David M. Alexander, Franz E. Bauer, Emanuele Daddi, Dale D. Kocevski, Flora Stanley, Daniel H. Mcintosh

Physics and Astronomy Faculty Publications

The most heavily-obscured, luminous quasars might represent a specific phase of the evolution of the actively accreting supermassive black holes and their host galaxies, possibly related to mergers. We investigated a sample of the most luminous quasars at z ≈ 1 − 3 in the GOODS fields, selected in the mid-infrared band through detailed spectral energy distribution (SED) decomposition. The vast majority of these quasars (~80%) are obscured in the X-ray band and ~30% of them to such an extent, that they are undetected in some of the deepest (2 and 4 Ms) Chandra X-ray data. Although no clear relation …